Chp 1: Growth Adaptations

Question 1

Hyperplasia

Answer 1

increase in the number of cells

Question 2

Hypertrophy

Answer 2

increase in the size of cells

Question 3

Mechanism of hyperplasia

Answer 3

Involves production of new cells from stem cells

Question 4

Mechanism of hypertrophy

Answer 4

Gene activation, protein synthesis (primarily for increased cytoskeleton), and production of organelles

Question 5

Can permanent tissues undergo both hyperplasia and hypertrophy?

Answer 5

No - permanent tissues (cardiac myocytes, skeletal muscle, and nerve) cannot make new cells –> only undergo hypertrophy

Question 6

Example of physiologic hyperplasia

Answer 6

Uterus during pregnancy

Question 7

Example of pathologic hyperplasia

Answer 7

Endometrial hyperplasia

Question 8

Pathologic hyperplasia

Answer 8

hyperplasia that can progress to dysplasia and, eventually, cancer

Question 9

Benign prostatic hyperplasia

Answer 9

Notable exception of pathologic hyperplasia that does not increase the risk for prostate cancer

Question 10

Atrophy

Answer 10

decrease in organ size via a decrease in the size and number of cells

Question 11

Mechanism to decrease the # of cells?

Answer 11

Apoptosis

Question 12

Mechanism to decrease the size of cells?

Answer 12

Occurs via ubiquitin-proteosome degredation of the cytoskeleton and autophagy of cellular components

Question 13

Ubiquitin-proteosome degradation

Answer 13

Intermediate filaments of cytoskeleton are “tagged” w/ ubiquitin and destroyed by proteosomes

Question 14

Autophagy of cellular components

Answer 14

involves generation of autophagic vacuoles which fuse w/ lysosomes whose hydrolytic enzymes breakdown cellular components

Question 15

Metaplasia

Answer 15

change in cell type due to change in stress on an organ (ex: Barrett esophagus)

Question 16

Mechanism of metaplasia

Answer 16

occurs via reprogramming of stem cells, which produces the new cell type

Question 17

Progression of metaplasia

Answer 17

Under persistent stress, metaplasia can progress to dysplasia and eventually cancer

Question 18

Is metaplasia reversible or irreversible?

Answer 18

Reversible (w/ removal of the driving stressor)

Question 19

Vitamin A deficiency

Answer 19

Vitamin A def can result in metaplasia. Vit A is necessary for differentiation and maintenance of specialized epithelial surfaces (ex: conjunctiva)

Question 20

Keratomalacia

Answer 20

goblet cell/columnar epithelium of conjunctiva undergoes metaplasia into keratinizing squamous epithelium, resulting in a thickened conjunctiva = keratomalacia. Due to vitamin A deficiency

Question 21

Myositis ossificans

Answer 21

due to inflammation from trauma connective tissue w/in skeletal muscle undergoes metaplasia and changes to bone

Question 22

Dysplasia

Answer 22

disordered cell growth, most often refers to proliferation of cell growth

Question 23

Is dysplasia reversible or irreversible?

Answer 23

Reversible w/ alleviation of inciting stress. if stress persists, dysplasia can progress to cancer (which is irreversible)

Question 24

Aplasia

Answer 24

failure of cell production during embryogenesis (ex: unilateral renal agenesis)

Question 25

Hypoplasia

Answer 25

decrease in cell production during embryogenesis, resulting in small organ (ex: streak ovary in Turner’s)